Apparatus for and method of locating leaks in a pipe

ABSTRACT

An apparatus for locating leaks in a pipe, such as a sewer pipe, wherein a viewing device such as a television camera is moved longitudinally through the pipe. The image seen by the camera is displayed on a television receiver. The camera utilizes a relatively long focal length lens so that only a short length of pipe is sharply in focus at each position of the camera. Means are provided for indicating the location of the camera as it is moved along the pipe so that when a leak is found, the location of the camera and corresponding, the location of the leak are accurately indicated to the user. The apparatus utilizes only the image of the pipe and the leak itself for locating the leak.

United States Patent 11 1 Latall 1 June 12, 1973 APPARATUS FOR ANDMETHOD OF LOCATING LEAKS IN PIPE [75] Inventor: Roy C. Latall, DesPlaines, 111.

[73] Assignee: Conco Inc., Mendota, Ill.

22 Filed: Nov. 30, 1970 21 Appl. No.1 93,610

FOREIGN PATENTS OR APPLICATIONS 1,043,366 9/1966 Great Britain 336/241Primary Examiner-Robert L. Griffin Assistant Examiner.loseph A. Orsino,Jr.

Attorney-Hofgren, Wegner, Allen, Stellman & McCord [57] ABSTRACT Anapparatus for locating leaks in a pipe, such as a sewer pipe, wherein aviewing device such as a television camera is moved longitudinallythrough the pipe. The image seen by the camera is displayed on a television receiver. The camera utilizes a relatively long focal [56]References Cited length lens so that only a short length of pipe issharply UNITED S TES PATENTS in focus at each position of the camera.Means are pro- 2,971,259 2/1961 I-Iaitnau 178/D1G. 1 vided forindicating the location of the camera as it is 3,090,378 5/1963 Sheldonmoved along the pipe so that when a leak is found, the 2,053,196 9/1936Kitroser location of the camera and corresponding, the location 2 1 1356/165 of the leak are accurately indicated to the user. The apu CI 1 1paratus ut1l1zes only the 1mage of the pipe and the leak Kramp forlocating the leak- 10 Claims, 3 Drawing Figures L 2/ 1g 1/ A? APPARATUSFOR AND METHOD OF LOCATING LEAKS IN A PIPE BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relatesto apparatusfor locating leaks in pipes, and more specifically relates tosuch'apparatus using viewing devices for movably scanning-theinterior ofthe pipe.

2. Description of the Prior Art In one well known form of sewer pipeleak locating apparatus, a television camera is moved longitudinallythrough a pipe so as to provide an image ofatarget element spacedaccurately a preselecteddistance .in front of the camera. The targetconventionally comprises a ball which, as a result of impingementofwater onthe ball at the leak, provides an indication thereof .throughthe television transmitting system. Such apparatusrequires that the ballbe maintained accurately at the fixed spacing from the'camera and anychange in-this spacing can result in an improper location of the leak.

Conventionally, a grouting device is provided with the leak loactingdevice so that the leak isautomatically sealed by suitable operation ofthe grouting device based on the information provided by theleaklocating device. Thus, where the target is inadvertently spacedwrongly from the camera, a grouting of the pipemay be effected at anincorrect location so that while the user believes that the leak hasbeen properly stopped, it may, in fact, have been completely missed bythe grouting device.

Further, such target devices may catch on irregularities in the pipe,making more difficult the ,use ofgthe leak locating apparatus. Leaklocating devices using such target means are shown in United StatesLetters Patent No. 3,168,909 issued to J.A. Zurbrigen et al. for aMethod for Locating and Sealing Pipe Leaks on Feb. 9, 1965 and 2,971,259issued to R. F. Hahnauet al. for a Method and Apparatus for Determining.the Position of Sewer Leaks" on Feb. 14, 1961.

SUMMARY OF THE INVENTION The present invention comprehends an improvedapparatus for locating leaks in a pipe eliminating the disadvantages ofthe above discussed conventional apparatuses in a novel and simplemanner.

More specifically, the present invention comprebrands the provision ofsuch an apparatus which eliminates the target means of the knownapparatuses and substitutes a positive optical focusing andidentification means. Thus, the apparatus is extremely simple andeconomical of construction while providing a number of highly desirableadvantages over the apparatuses of the prior art.

The present apparatus utilizes a suitable preselected focal lens in thetelevision camera so as to provide a sharp, preselected smalldepth-of-field image of the interior of the pipe being. scanned at apreselected distance from the lens whereby a leak maybe sharply.displayed only when the lens is accurately at the preselected distance.Thus, the present apparatus utilizes only the pipe structure and leakitself for providing the location determining information.

To facilitate accuratedetermination of the leak location, the televisionreceiver may be provided with a suitable marking corresponding to theconfiguration of the pipe in the sharply defined portion of the image.

nate. The indicium means on the receiver may corre- ,spondingly comprisea circle having a diameter accurately corresponding to the displayedimage circle of the-sharply defined portion of the pipe.

Where the apparatus is intended for use with pipes of differentdiameters, correspondingly different diameter circles maybe provided inthe receiver viewing means for providing corresponding indicia meanssuitable for use .with the different diameter pipes.

BRIEF DESCRIPTION OF THE DRAWING Other features and advantages of theinvention will be apparent from the following description taken inconnection with the accompanying drawing wherein:

.FIG. 1 is a schematic view illustrating the arrangement of theapparatus embodying the invention for locating leaks in a pipe;

FIG. 2 is a diagrammatic diametric section of the pipe scanning means;and

FIG. 3 is afront view of the display means.

DESCRIPTION OF THE PREFERRED EMBODIMENT In ,theexemplary embodiment ofthe invention as disclosed in the drawing, an apparatus generally designated 10 is provided for locating leaks L in a pipe, such as a sewerpipe, 11. The apparatus includes a viewing, or scanning, devicegenerally designated 12 herein comprising a television camera andsuitable cable means generally designated 13 for drawing the cameralongitudinally through the pipe to progressively scan the lengththereof. The television camera is drawn through the pipe by suitablemeans such as a winch 14 with the cables being brought from the pipe 11upwardly through a suitable manhole 15. A monitoring television receivergenerally designated 16 is provided at ground-level for observation bythe user in determining the location of the leaks in the pipe. Camera 12and receiver 16 may comprise portions of a closed circuit televisionsystem generally designated 17 which may further include a suitablegenerator 18 and a transmitting cable 19 which may be paid out from andwound up on a suitable reel 20 to follow the movement of the camera 12through the pipe.

Asdesired, a conventional grouting device generally designated 21 may befurther carried with the camera l2-by means of a connecting cable 22 forgrouting each leak L as it is found. More specifically, the televisionsystem 17 provides suitable information for accurately locating the leakas a result of the scanning thereof by the television camera 12 andpermits the user to effect further movement of the camera and groutingdevice through the pipe to accurately position the grouting device atthe previously located leak to effect an accurately located grouting ofthe leak as shown in FIG. 1.

To permit the elimination of the conventional target device associatedwith the television camera in the known apparatuses as discussed above,television camera 12 is provided with an effectively long focal lengthlens, such as a 12.5 mm focal length lens utilized with a small indiciumpickup tube, for use in scanning pipes,

such as sewer pipes ranging in size from approximately 6 inches to 30inches. With such a lens, the depth-offield of the sharply focused imageof the interior wall surface of the pipe is small and, illustratively,may be less than approximately 4 inches. Thus, as illustrated in FIG. 2,the depth-of-field may define a relatively narrow band A of the interiorwall surface of the pipe accurately located at a preselected distance D,such as approximately 17 inches from the lens 23 of the camera 12. Theportion of the interior wall surface of the pipe scanned by the lens 23forwardly of band, or zone, A, such as joint portion B of the pipe, isout of focus and the portion rearwardly of zone A, such as portion C, issimilarly out of focus. Thus, only when the leak is positioned at adistance approximately D from lens 23 will the leak be sharply in focus.At the same time, the band A of the pipe will similarly be in sharpfocus.

The resultant display of this condition is shown in FIG. 3 wherein thetelevised image 24 of pipe band A appears as a relatively clearlydefined circle. Portions of the interior wall surface of the pipe inzone B appear outwardly of the circle 24 and portions of the piperearwardly of the band A appear inwardly of the circle 24.

Thus, as the camera is moved longitudinally through the pipe, i.e. tothe right as seen in FIG. 1, the stream, or series or droplets, 25 ofleak L is first discerned as out of focus, relatively large, indistinctshape extending downwardly the entire height of the receiver screen 26.However, as the camera moves further away from the leak, the point oforigin of the leak 27 at the top of the pipe image moves downwardly tothe top 28 of the screen. At the same time that the stream becomessharply focused, i.e. it becomes spaced from the lens 23 the spacing D,the point of origin 27 moves further downwardly to appear at the top ofthe sharply defined circle 24 comprising the image of the sharplyfocused pipe band A. Thus, not only is there a sudden change in thesharpness of the leak, but also, there is a positive indication of thespacing of the lens 23 from the leak by the distance D by thecorrelation of the position of the top of the leak 27 at the imagecircle 24.

Should the television camera inadvertently be moved further away fromthe leak, not only will the image of the leak again become unfocused,but also the top of the stream, or droplet series, will be displacedbelow the top of the circle 24 as the circle 24 now represents the newband A forwardly of the band in which the leak is located. Thus, thelocation of the top of the line of leak on the screen 26 accuratelyassists the user in the location of the leak by augmenting thedetermination made by the brining of the leak into sharp focus at thedistance D.

It has been found that a further facilitation of the de-:

termination of the leak location may be effected by providing inassociating with screen 26 an indicium, or reference point, such as thetop 28 of the receiver screen, or a suitable mark 29, herein comprisinga circle which accurately corresponds to the diameter of the image ofthe interior of the pipe at the distance D from lens 23. By use of thereference circle 29, need for ascertaining the sharpness of the leak toindicate the spacing D is obviated. All that the user need do is toascertain the point at which the camera is positioned when the leakorigin 27 is accurately disposed in correspondence with the top ofcircle 29, or similarly when the length of the leak is accurately equalto the diameter of the reference circle.

or may be provided on suitable transparent sheets.

Thus, a series of different sheets, each with a single, suitablereference circle provided therein, may be utilized selectively forcorrespondence with the different size pipes to be scanned.Alternatively, a single circle' may be'used on the receiver with thelens system being suitably changed for different size pipes to producethe same size image on the screen 26 for each different size pipe.

In use, the determination of the leak location may be suitably recordedfor grouting by a subsequent introduction of grouting apparatus into thepipe as practiced in one conventional method of pipe leak repair. Inillustrating the invention, a grouting device has been shown inassociation with the camera so that once the location of a leak isdetermined, the cable 13 may be drawn forwardly a preselected distancecorresponding to the spacing of the attached grouting device from thetelevision camera so that the grouting device may be immediatelyaccurately located at the leak for effecting the repair thereof. Anysuitable method of utilizing the information provided by the leaklocating means of the present invention may be utilized therewith ineffecting the repair of the leak within the scope of the invention.

Thus, the present invention comprehends an improved apparatus forfacilitated location of leaks in underground pipes permittingfacilitated repair thereof. The improved, simplified apparatus of thepresent invention provides for reduced cost and maintenance while yetproviding an improved accurate leak location determination.

The foregoing disclosure of specific embodiments is illustrative of thebroad inventive concepts comprehended by the invention.

I claim:

1. In an apparatus for locating leaks in a pipe including a viewingdevice for providing an image, means for variably locating the viewingdevice in the pipe, means for indicating the location of the viewingdevice in the pipe, andmeans for displaying the image provided by saidviewing device, means for accurately locating the viewing devicerelative to a leak in the pipe comprising focusing means associated withthe viewing device for providing a sharp, preselected smalldepth-of-field focused image of a narrow portion of the interior of thepipe at a preselected distance from the focusing means whereby a leakmay be sharply displayed only when the viewing device is accurately atsaid preselected distance therefrom to coincide with the sharp image ofthe focused pipe portion, said depth of field being less thanapproximately 4 inches.

2. Theleak locating apparatus of claim 1 wherein said focusing meanscomprises an effectively long focal length lens.

3. The leak locating apparatus of claim 1 wherein the pipe is circular,the viewing device is arranged to view the pipe from the axis thereof,and said means for accurately indicating said, condition comprises acircle on the displaying means corresponding accurately to thecircularshape of the sharp limited depth-of-field image of the interiorsurface of the pipe interior wall surface at said preselected distancefrom said lens.

4. The leak locating apparatus of claim 1 further including meansassociated with said displaying means for accurately indicating thecondition wherein the image of the leak extends downwardly from the topof the sharp limited depth-of-field image of the pipe interior wallsurface.

5. The leak locating apparatus of claim 4 wherein said means foraccurately indicating said condition comprises a marking on thedisplaying means corresponding accurately to the top of said sharplimited depth-of-field image.

6. The leaklocating apparatus of claim 4 wherein said means foraccurately indicating said condition comprises a closed line onthe-displaying means corresponding accurately to the shape of the sharplimited depth-of-field imageof the interior surface of the pipe interiorwall surface at said preselected distance from said lens.

7. In an apparatus for locating leaks in a pipe including a televisioncamera for providing an image, means for variably locating the camera inthe pipe, means for indicating the location of the camera in the pipe,and a television receiver for displaying the image provided by saidcamera, means for accurately locating the camera relative to a leak inthe pipe comprising: a long focal length lens in said television camerafor providing a sharp, preselected small depth-of-field focused image ofa narrow portion of the interior of the pipe at a preselected distancefrom the lens whereby a leak may be sharply displayed by said receiveronly when the camera lens is accurately at said preselected distancetherefrom to coincide with the sharp image of the focused pipe portion,said depth of field being less than approximately 4 inches; and indiciummeans on said receiver for indicating when a leak viewed by the cameraoriginates at a point in said pipe spaced from said lens accurately saidpreselected distance.

8. The leak locating apparatus of claim 7 wherein said pipe is circular,said lens is carried by said television camera to be axially centered inthe pipe, and said indicium means comprises a circle displayed on thereceiver to be viewed concurrently with the displayed image foraccurately identifying in the image the sharply focused circular zone ofthe pipe interior wall surface.

9. The leak locating apparatus of claim 7 wherein said indicium meanscomprises a plurality of different size concentric circles displayed onthe receiver for use in identifying images with corresponding differentdiameter pipes.

10. The method of locating a leak in a pipe comprising the steps of:movably scanning progressively lengthwise of a pipe, successive narrow,sharply-focused, transverse cross-sections of the interior of the pipe;providing information as to the scanning position when thesharply-focused narrow cross-section of the interior of the pipe is thatin which a leak is disposed; providing an image of the scanned sharplyfocused leak on a display; and comparing the image on the display to areference indicium associated with the display to facilitatedetermination of the scanning position wherein the leak is disposed insaid narrow, sharply-focused scanned cross section of the interior ofthe pipe.

1. In an apparatus for locating leaks in a pipe including a viewingdevice for providing an image, means for variably locating the viewingdevice in the pipe, means for indicating the location of the viewingdevice in the pipe, and means for displaying the image provided by saidviewing device, means for accurately locating the viewing devicerelative to a leak in the pipe comprising focusing means associated withthe viewing device for providing a sharp, preselected smalldepth-of-field focused image of a narrow portion of the interior of thepipe at a preselected distance from the focusing means whereby a leakmay be sharply displayed only when the viewing device is accurately atsaid preselected distance therefrom to coincide with the sharp image ofthe focused pipe portion, said depth of field being less thanapproximately 4 inches.
 2. The leak locating apparatus of claim 1wherein said focusing means comprises an effectively long focal lengthlens.
 3. The leak locating apparatus of claim 1 wherein the pipe iscircular, the viewing device is arranged to view the pipe from the axisthereof, and said means for accurately indicating said, conditioncomprises a circle on the displaying means corresponding accurately tothe circular shape of the sharp limited depth-of-field image of theinterior surface of the pipe interior wall surface at said preselecteddistance from said lens.
 4. The leak locating apparatus of claim 1further including means associated with said displaying means foraccurately indicating the condition wherein the image of the leakextends downwardly from the top of the sharp limited depth-of-fieldimage of the pipe interior wall surface.
 5. The leak locating apparatusof claim 4 wherein said means for accurately indicating said conditioncomprises a marking on the displaying means corresponding accurately tothe top of said sharp limited depth-of-field image.
 6. The leak locatingapparatus of claim 4 wherein said means for accurately indicating saidcondition comprises a closed line on the displaying means correspondingaccurately to the shape of the sharp limited depth-of-field image of theinterior surface of the pipe interior wall surface at saiD preselecteddistance from said lens.
 7. In an apparatus for locating leaks in a pipeincluding a television camera for providing an image, means for variablylocating the camera in the pipe, means for indicating the location ofthe camera in the pipe, and a television receiver for displaying theimage provided by said camera, means for accurately locating the camerarelative to a leak in the pipe comprising: a long focal length lens insaid television camera for providing a sharp, preselected smalldepth-of-field focused image of a narrow portion of the interior of thepipe at a preselected distance from the lens whereby a leak may besharply displayed by said receiver only when the camera lens isaccurately at said preselected distance therefrom to coincide with thesharp image of the focused pipe portion, said depth of field being lessthan approximately 4 inches; and indicium means on said receiver forindicating when a leak viewed by the camera originates at a point insaid pipe spaced from said lens accurately said preselected distance. 8.The leak locating apparatus of claim 7 wherein said pipe is circular,said lens is carried by said television camera to be axially centered inthe pipe, and said indicium means comprises a circle displayed on thereceiver to be viewed concurrently with the displayed image foraccurately identifying in the image the sharply focused circular zone ofthe pipe interior wall surface.
 9. The leak locating apparatus of claim7 wherein said indicium means comprises a plurality of different sizeconcentric circles displayed on the receiver for use in identifyingimages with corresponding different diameter pipes.
 10. The method oflocating a leak in a pipe comprising the steps of: movably scanningprogressively lengthwise of a pipe, successive narrow, sharply-focused,transverse cross-sections of the interior of the pipe; providinginformation as to the scanning position when the sharply-focused narrowcross-section of the interior of the pipe is that in which a leak isdisposed; providing an image of the scanned sharply focused leak on adisplay; and comparing the image on the display to a reference indiciumassociated with the display to facilitate determination of the scanningposition wherein the leak is disposed in said narrow, sharply-focusedscanned cross section of the interior of the pipe.